1. Field of the Invention
The invention relates to a water pump for circulating coolant or the like.
2. Description of the Related Art
For example, in a vehicle using a motor as a power source, a water pump is used for circulating coolant that cools the motor, an inverter, and the like. In the water pump, a rotatable impeller is provided. When the impeller is rotated, the coolant is discharged from a discharge port so that the coolant is circulated.
Water pumps in which an impeller is housed in a chamber composed of an upper housing and a housing portion in a pump body are known. Also, Japanese Utility Model Application Publication No. 5-58899 discloses a supercharger in which a compressor impeller is housed in a chamber composed of a compressor housing and a bearing chamber body. Further, Japanese Patent Application Publication No. JP 11-30191 A discloses a self-primed centrifugal pump in which an impeller is housed in a chamber composed of an impeller casing and an end casing.
In the aforementioned water pump, a discharge port is provided in the upper housing. The direction in which the discharge port faces with respect to the pump body is set by attaching the upper housing to the pump body.
Meanwhile, in the case where one type of water pump is shared across different vehicle models, because the arrangement of vehicle components varies between vehicle models, it is desirable to have a water pump in which the discharge port can be oriented in a direction as dictated by the layout of the components in a particular vehicle model. Therefore, preferably, the upper housing can be placed in various positions by turning the upper housing by various angles when the upper housing is attached to the pump body.
Also, in order for the water pump to operate quietly, it is desired to reduce operating noise of the water pump, particularly operating noise caused by rotation of the impeller.